The reduction of aerosolization produced by the flushing of toilets is desirable in order to reduce the possibility of airborne transmission of organisms from the toilet wastewater. In the application of MuCune, U.S. Ser. No. 959,405, filed Nov. 9, 1978, now abandoned in favor of continuation-in-part application which issued as U.S. Pat. No. 4,253,951 on Mar. 3, 1981, and is incorporated by reference herein, it is disclosed that the aerosolization of wastewater from flushing toilets can be significantly reduced by the presence of low levels (1-30 ppm) of high molecular weight polyethylene oxide resins in the wastewater.
In treating toilet flush water with chemicals in order to produce desirable effects such as bowl cleaning, it is desirable that the chemicals be dispensed into the flush water automatically each time the toilet is flushed. The prior art discloses numerous devices which have been designed for this purpose. Exemplary of such devices are those disclosed in U.S. Pat. Nos. 3,831,205, issued Aug. 27, 1974, to Foley; 3,341,074, issued Sept. 12, 1967, to Pannutti; 3,504,384, issued Apr. 7, 1970, to Radley et al.; 2,688,754, issued Sept. 14, 1954, to Willits et al.; and 4,036,407, issued July 19, 1977, to Slone. Particularly desirable devices are those wherein the chemical composition is in the device in the form of a solid cake composition. In this type of device a measured amount of water enters the device during one flush cycle and remains in contact with the cake composition between flushes, thereby forming a concentrated solution of the composition which is dispensed into the flush water during the next flush. The advantages of such devices are that the chemical composition can be packaged and shipped in more concentrated form than an aqueous solution of the chemicals, and the problems of liquid spillage resulting from breakage of the dispensers during shipment or handling are eliminated. Exemplary devices for automatic dispensing of chemicals from solid cake compositions into the toilet are those described in U.S. Pat. Nos. 4,171,546, issued Oct. 23, 1979, to Dirksing, 4,208,747, issued June 24, 1980, to Dirksing; and 4,186,856, issued Feb. 5, 1980, to Dirksing. A dispensing means for use with the compositions herein is described in the application of Choy entitled "PASSIVE DOSING DISPENSER EXHIBITING IMPROVED RESISTANCE TO CLOGGING", U.S. Ser. No. 153,997, filed May 28, 1980. All of said patents and applications being incorporated herein by reference.
It has been found that when solid cake compositions comprising high molecular weight polyethylene oxide resins (i.e., molecular weights of from about 500,000 to 7,000,000) are utilized in automatic dispensers, the resin forms a thick gel when exposed to the limited volume of water within the dispenser, thereby retarding or even completely blocking the subsequent flow of dissolved materials out of the dispenser and into the flush water. In the application of Choy et al., U.S. Ser. No. 153,993, filed May 28, 1980, it is disclosed that the resin gelling problem is avoided by resin compositions comprising PEO resin, surfactant and water-soluble salts. The Choy et al. compositions, however, are difficult to manufacture using conventional bar soap extruders and related cake cutting or stamping equipment. The Choy et al. composition cakes must be formed by high pressure tableting equipment.
It is an object of the present invention to provide solid cake compositions comprising polyethylene oxide resins, which compositions are suitable for use in dispensers for automatically dispensing chemicals into the toilet.
It is a further object of the present invention to provide solid cake compositions comprising polyethylene oxide resins which compositions have a reduced tendency to form gels when exposed to water.
Yet another object of the present invention is to provide a composition which can be extruded into a bar and the bar cut into solid cakes.